scholarly journals Незаполненные электронные состояния и потенциальный барьер в пленках замещенных дифенилфталидов на поверхности высокоупорядоченного пиролитического графита

2021 ◽  
Vol 63 (2) ◽  
pp. 299
Author(s):  
А.С. Комолов ◽  
Э.Ф. Лазнева ◽  
Н.Б. Герасимова ◽  
В.С. Соболев ◽  
С.А. Пшеничнюк ◽  
...  
Keyword(s):  
Energy Range ◽  
Work Function ◽  
Potential Barrier ◽  
Substrate Surface ◽  
Pyrolytic Graphite ◽  
Electronic States ◽  
Organic Films ◽  
Total Current ◽  
Electronic Work Function ◽  
Two Peaks

The results of a study of the unoccupied electronic states of ultrathin films of bis-carboxyphenyl-phthalide (DCA-DPP) and bis-methylphenyl-phthalide (DM-DPP) up to 8 nm thick are presented. The studies were carried out by total current spectroscopy (TCS) technique in the energy range from 5 eV to 20 eV above EF during thermal vacuum deposition of these organic films on the surface of highly oriented pyrolytic graphite (HOPG). The energy Evac relative to EF, that is, the electronic work function of the DM-DPP films, at a film thickness of 5–8 nm was 4.3 ± 0.1 eV. The electronic work function of the DCA-DPP films was 3.7 ± 0.1 eV. The structure of the maxima of the unoccupied electronic states of DCA-DPP films and DM-DPP films in the studied energy range is determined. The properties determined of DCA-DPP and DM-DPP films are compared with the properties of films of unsubstituted diphenylphthalide (DPP). According to our analysis, –CH3 substitution of the DPP molecule practically did not affect the height of the potential barrier between the film and the HOPG surface, and –COOH substitution of the DPP molecule led to an increase in the height of the potential barrier between the film and the HOPG substrate surface by 0.5–0.6 eV. Substitution of DPP molecules with –COOH functional groups which represents formation of DCA-DPP molecules led to a shift of two peaks of the experimental total current spectra located at energies in the range from 5 eV to 8 eV above EF, by about 1 eV towards lower electron energies.

scholarly journals Незаполненные электронные состояния ультратонких пленок тиофен-фенилен со-олигомеров на поверхности поликристаллического золота

2020 ◽  
Vol 62 (10) ◽  
pp. 1741
Author(s):  
А.С. Комолов ◽  
Э.Ф. Лазнева ◽  
Н.Б. Герасимова ◽  
В.С. Соболев ◽  
С.А. Пшеничнюк ◽  
...  
Keyword(s):  
Work Function ◽  
Electron Work Function ◽  
Electronic States ◽  
Atomic Layer ◽  
Ex Situ ◽  
Physicochemical Interaction ◽  
Total Current ◽  
Electronic Work Function ◽  
Film Substrate

The results of studying unoccupied electronic states in the energy range from 5 eV to 20 eV above the Fermi level of ultrathin films of dimethyl-substituted thiophene-phenylene co-oligomers CH3-phenylene-thiophene-thiophene-phenylene-CH3 (CH3-PTTP-CH3) are presented. The films were deposited on two types of surface of polycrystalline Au: ex situ Au layer thermally deposited in a separate chamber, and on the in situ Au surface prepared inside the analytical chamber. The structure of the films was studied by X-ray diffraction (XRD). The formation of a superposition of the amorphous and crystalline phases with a period of 3.8 nm is discussed. Investigations of the energy positioning of the maxima of unoccupied electronic states and of the process of the formation of the potential boundary barrier were carried out by the method of total current spectroscopy (TCS). The maxima of the fine structure of the total current spectra (FSTCS) of the CH3-PTTP-CH3 film 5–7 nm thick did not differ when using different types of Au substrates and the surface of the ZnO semiconductor prepared by the atomic layer deposition (ALD) method. When the CH3-PTTP-CH3 layer was deposited both on the ex situ Au surface and on the in situ Au surface, a slight (about 0.1 eV) increase in the electronic work function was observed with an increase in the coating thickness to 5–7 nm. At such CH3-PTTP-CH3 film thicknesses, the electron work function was determined as 4.7 ± 0.1 eV for the ex situ Au substrate and 4.9 ± 0.1 eV for the in situ Au substrate. The possible influence of the processes of physicochemical interaction at the film – substrate interface on the formation of the potential boundary barrier in the structures under study is discussed.

scholarly journals Плотность свободных электронных состояний полупроводниковых пленок молекул нафталина и дифенилфталида, модифицированных электроактивными функциональными группами

2020 ◽  
Vol 62 (7) ◽  
pp. 1116
Author(s):  
А.С. Комолов ◽  
Э.Ф. Лазнева ◽  
Н.Б. Герасимова ◽  
А.В. Барамыгин ◽  
В.С. Соболев ◽  
...  
Keyword(s):  
Fermi Level ◽  
Dicarboxylic Acid ◽  
Density Functional ◽  
Pyrolytic Graphite ◽  
Electronic States ◽  
Dft Method ◽  
Layer By Layer ◽  
Total Current ◽  
Peak Structure ◽  
The Difference

The results on comparing the peak structure of the density of unoccupied electronic states (DOUS) of ultrathin films of naphthalene anhydride-1,4,5,8-teracabonic acid (NTCDA) and naphthalene-1,8-dicarboxylic acid anhydride (NDCA) and of two types of phthalide-based films: 3,3-bis (phenyl) phthalide (DPP) and 3,3-bis (phenyl) phthalide-4 ′, 4′-dicarboxylic acid (DPP-DCA) are presented. The measurements of the structure of the unoccupied electronic states in the energy range from 5 eV to 20 eV above the Fermi level of the films studied having thickness of 8–10 nm were conducted using the total current spectroscopy (TCS) technique. Analysis of the experimental results was conducted using the model total current spectra and DOUS dependences generated using the calculated orbital energies of the studied molecules by means of the density functional theory (DFT) method at the B3LYP/6-31G(d) level. The difference in the DOUS spectra of NTCDA and NDCA films is characterized by the shift of the main DOUS maxima of the NTCDA film to lower energies by about 1 eV at energies less than 12.5 eV, and at higher energies the DOUS maxima are shifted by 1.5-2 eV. The energy positions of the maxima of the total current spectra of the DPP-DCA and DPP films practically do not change when using various substrates: highly ordered pyrolytic graphite (HOPG) and layer-by-layer deposited CdS. The relative intensities of the maxima differ when using different substrates. The characteristic shift of the maxima of the total current spectra of DPP-DCA films is about 1 eV at energies less than 12.5 eV above the Fermi level and 1.5-2 eV and at higher energies, compared with the position of the corresponding maxima of the DPP films.

scholarly journals Незаполненные электронные состояния ультратонких пленок дифенилфталида на поверхности высокоупорядоченного пиролитического графита

2019 ◽  
Vol 61 (10) ◽  
pp. 1960
Author(s):  
А.С. Комолов ◽  
Э.Ф. Лазнева ◽  
Н.Б. Герасимова ◽  
В.С. Соболев ◽  
С.А. Пшеничнюк ◽  
...  
Keyword(s):  
Negative Charge ◽  
Pyrolytic Graphite ◽  
Electron Work Function ◽  
Electronic States ◽  
Low Energy ◽  
Atomic Composition ◽  
Total Current ◽  
Organic Film ◽  
X Ray ◽  
Calculation Results

AbstractThe results of diagnostics of the atomic composition of a diphenylphthalide (DPP) film thermally precipitated in vacuum by the of X-ray photoelectric spectroscopy (XPS) method are presented. The results of examination of the unoccupied electronic states of the ultrathin DPP films with the thickness up to 10 nm on the surface of the highly oriented pyrolytic graphite (HOPG) by the total current spectroscopy (TCS) method in the energy range from 5 to 20 eV above E _F are presented. In this range, the main maxima in the total current spectra are identified. The analysis of the TCS results with consideration of the theoretical calculation results has shown that the low-energy maxima observed at the energies from 6 to 7.5 eV are induced predominately by π* electron orbitals of DPP films. The values of the energy E _vac in relation to E _F, i.e., of the electron work function in the DPP films at the film thickness of 5–10 nm, are found experimentally at a level of 4.3 ± 0.1 eV. The negative charge transfer from an organic film to the substrate corresponds to the formation of the HOPG/DPP boundary potential barrier during the thermal deposition of the DPP film.

scholarly journals Прохождение низкоэнергетических электронов и плотность незаполненных состояний сверхтонких слоев TCNQ на поверхности окисленного кремния

2020 ◽  
Vol 62 (7) ◽  
pp. 1105
Author(s):  
А.С. Комолов ◽  
Э.Ф. Лазнева ◽  
Н.Б. Герасимова ◽  
В.С. Соболев ◽  
Ю.А. Панина ◽  
...  
Keyword(s):  
Energy Range ◽  
Potential Barrier ◽  
Density Functional ◽  
Electronic States ◽  
Dft Method ◽  
Functional Theory ◽  
Surface Work ◽  
The Density Functional Theory ◽  
Interface Potential ◽  
Pi Orbitals

The results of the study of the formation of unoccupied electronic states and of the interface potential barrier during thermal deposition of tetracyanoquinodimethane (TCNQ) films, up to 7 nm thick, on the (SiO2)n-Si surface are presented. The electronic properties of the surface under study were determined using the total current spectroscopy (TCS) technique and as testing electron beam with energies in the range from 5 eV to 20 eV above the Fermi level. The formation of a potential barrier in the (SiO2)n-Si / TCNQ structure was accompanied by an increase in the surface work function from 4.2 ± 0.1 eV to 4.7 ± 0.1 eV. Based on the results of TCS experiments, the DOUS function of the studied TCNQ film is constructed. To analyze the experimental DOUS, the orbital energies of the studied TCNQ molecules were calculated using the density functional theory (DFT) method at the B3LYP/6-31G(d) level, which was followed by the correction procedure and by the allowance for the condensed phase polarization energy. DOUS of the TCNQ films has four main maxima in the energy range studied. The DOUS maximum at an energy of 7.0 eV above EF is mainly formed by pi* orbitals. Three DOUS maxima located in the energy range from 8.0 eV to 20 eV above EF are formed by approximately the same number of pi* and sigma* type orbitals.

Unoccupied Electronic States and Potential Barrier in Films of Substituted Diphenylphthalides on the Surface of Highly Ordered Pyrolytic Graphite

2021 ◽  
Vol 63 (2) ◽  
pp. 362-367
Author(s):  
A. S. Komolov ◽  
E. F. Lazneva ◽  
N. B. Gerasimova ◽  
V. S. Sobolev ◽  
S. A. Pshenichnyuk ◽  
...  
Keyword(s):  
Potential Barrier ◽  
Pyrolytic Graphite ◽  
Electronic States ◽  
Highly Ordered Pyrolytic Graphite

The lowest-lying electronic states of isoflurane and sevoflurane in the 5.0–10.8 eV energy range investigated by experimental and theoretical methods

2019 ◽  
Vol 716 ◽  
pp. 42-48
Author(s):  
E. Lange ◽  
F. Ferreira da Silva ◽  
N.C. Jones ◽  
S.V. Hoffmann ◽  
D. Duflot ◽  
...  
Keyword(s):  
Energy Range ◽  
Electronic States ◽  
Theoretical Methods

scholarly journals X-ray spectroscopy study of ThO2 and ThF4

2010 ◽  
Vol 25 (1) ◽  
pp. 8-12
Author(s):  
Anton Teterin ◽  
Mikhail Ryzhkov ◽  
Yury Teterin ◽  
Ernst Kurmaev ◽  
Konstantin Maslakov ◽  
...  
Keyword(s):  
Binding Energy ◽  
Energy Range ◽  
Density Distribution ◽  
Electronic State ◽  
Electronic States ◽  
State Density ◽  
Molecular Orbitals ◽  
Spectral Structure ◽  
X Ray ◽  
Electronic State Density

The structure of the X-ray photoelectron, X-ray O(F)Ka-emission spectra from ThO2 and ThF4 as well as the Auger OKLL spectra from ThO2 was studied. The spectral structure was analyzed by using fully relativistic cluster discrete variational calculations of the electronic structure of the ThO8 D4h) and ThF8 (C2) clusters reflecting thorium close environment in solid ThO2 and ThF4. As a result it was theoretically found and experimentally confirmed that during the chemical bond formation the filled O(F)2p electronic states are distributed mainly in the binding energy range of the outer valence molecular orbitals from 0-13 eV, while the filled O(F)2s electronic states - in the binding energy range of the inner valence molecular orbitals from 13-35 eV. It was shown that the Auger OKLL spectral structure from ThO2 characterizes not only the O2p electronic state density distribution, but also the O2s electronic state density distribution. It agrees with the suggestion that O2s electrons participate in formation of the inner valence molecular orbitals, in the binding energy range of 13-35 eV. The relative Auger OKL2-3L2-3 peak intensity was shown to reflect quantitatively the O2p electronic state density of the oxygen ion in ThO2.

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